var $ = function(id) {
	return "string" == typeof id ? document.getElementById(id) : id;
};
var Class = {
	create : function() {
		return function() {
			this.initialize.apply(this, arguments);
		}
	}
}
Object.extend = function(destination, source) {
	for (var property in source) {
		destination[property] = source[property];
	}
	return destination;
}
var Calendar = Class.create();
Calendar.prototype = {
	initialize : function(container, options) {
		this.Container = $(container);// table结构容器
		this.Days = [];// 日期列表
		this.SetOptions(options);
		this.Year = this.options.Year;
		this.Month = this.options.Month;
		this.SelectDay = this.options.SelectDay
				? new Date(this.options.SelectDay)
				: null;
		this.onSelectDay = this.options.onSelectDay;
		this.onToday = this.options.onToday;
		this.onFinish = this.options.onFinish;
		this.Draw();
	},

	SetOptions : function(options) {
		this.options = {// 默认值
			Year : new Date().getFullYear(),
			Month : new Date().getMonth() + 1,
			SelectDay : null,// 选择日期
			onSelectDay : function() {
			},
			onToday : function() {
			},
			onFinish : function() {
			}
		};
		Object.extend(this.options, options || {});
	},
	// 上月
	PreMonth : function() {
		// 取得上月日期对象
		var d = new Date(this.Year, this.Month - 2, 1);
		// 设置属性
		this.Year = d.getFullYear();
		this.Month = d.getMonth() + 1;
		// 重绘日历
		this.Draw();
	},
	// 下一个月
	NextMonth : function() {
		var d = new Date(this.Year, this.Month, 1);
		this.Year = d.getFullYear();
		this.Month = d.getMonth() + 1;
		this.Draw();
	},

	Draw : function() {
		// 保存日期列表
		var arr = [];
		// 用当月第一天在一周中的日期值作为当月离第一天的天数
		for (var i = 1, firstDay = new Date(this.Year, this.Month - 1, 1)
				.getDay(); i <= firstDay; i++) {
			arr.push(" ");
		}
		// 用当月最后一天在一个月中的日期值作为当月的天数
		for (var i = 1, monthDay = new Date(this.Year, this.Month, 0).getDate(); i <= monthDay; i++) {
			arr.push(i);
		}
		// /
		var frag = document.createDocumentFragment();
		this.Days = [];
		while (arr.length > 0) {
			// 每个星期插入一个tr
			var row = document.createElement("tr");
			// 星期
			for (var i = 1; i <= 7; i++) {
				var cell = document.createElement("td");
				cell.innerHTML = " ";
				if (arr.length > 0) {
					var d = arr.shift();
					cell.innerHTML = d;
					if (d > 0) {
						this.Days[d] = cell;
						// 获取今日
						if (this.IsSame(new Date(this.Year, this.Month - 1, d),
								new Date())) {
							this.onToday(cell);
						}
						// 判断用户是否作了选择
						if (this.SelectDay
								&& this
										.IsSame(new Date(this.Year, this.Month
																- 1, d),
												this.SelectDay)) {
							this.onSelectDay(cell);
						}
					}
				}
				row.appendChild(cell);
			}
			frag.appendChild(row);
		}
		// 此先清空然后再插入(ie的table不能用innerHTML)
		while (this.Container.hasChildNodes()) {
			this.Container.removeChild(this.Container.firstChild);
		}
		this.Container.appendChild(frag);
		this.onFinish();
	},
	// 判断是否同一日
	IsSame : function(d1, d2) {
		return (d1.getFullYear() == d2.getFullYear()
				&& d1.getMonth() == d2.getMonth() && d1.getDate() == d2
				.getDate());
	}
};

/*ddlevelsmenu.addEvent(window, function() {
	var cale = new Calendar("idCalendar", {
		SelectDay : new Date().setDate(10),
		onSelectDay : function(o) {
			o.className = "onSelect";
		},
		onToday : function(o) {
			o.className = "onToday";
		},
		onFinish : function() {
			$("idCalendarYear").innerHTML = this.Year;
			$("idCalendarMonth").innerHTML = this.Month;
			var flag = [10, 15, 20];
			for (var i = 0, len = flag.length; i < len; i++) {
				this.Days[flag[i]].innerHTML = "<a href='javascript:void(0);' onclick=\"alert('您选择的日期是："
						+ this.Year
						+ "/"
						+ this.Month
						+ "/"
						+ flag[i]
						+ "');return false;\">" + flag[i] + "</a>";
			}
		}
	});
	$("idCalendarPre").onclick = function() {
		cale.PreMonth();
	}
	$("idCalendarNext").onclick = function() {
		cale.NextMonth();
	}
}, "load");*/